What is the recommended imaging for an incidental bone cystic lesion at the proximal humerus?

From the Guidelines

For an incidental bone cystic lesion at the proximal humerus, the recommended initial imaging approach is to obtain plain radiographs in two perpendicular planes (anteroposterior and lateral views) as the initial assessment. This approach is based on the most recent and highest quality study available, which emphasizes the importance of radiographic evaluation in assessing primary bone tumors 1. The radiographic evaluation helps determine if the lesion is aggressive or non-aggressive based on features such as border definition, cortical thinning, periosteal reaction, and matrix characteristics.

Key Considerations

• Radiographs provide information regarding tumor location, size, and shape as well as evidence of tumor biological activity 1.
• Tumor margin and periosteal reaction provide a reliable index of biological potential of the tumor, whereas matrix, if identified, is a key to the underlying histology 1.
• MRI with contrast may be added for detailed characterization, particularly for assessing soft tissue extension, marrow involvement, and fluid-fluid levels that might suggest certain diagnoses like aneurysmal bone cysts.
• CT scanning may be added to better evaluate cortical integrity and mineralization patterns if the lesion appears aggressive or indeterminate on radiographs and MRI.

Imaging Approach

• Initial radiographic evaluation using plain radiographs in two perpendicular planes.
• Followed by MRI with contrast for detailed characterization if necessary.
• CT scanning may be added if the lesion appears aggressive or indeterminate.
• The choice of imaging modality depends on the initial radiographic findings and the clinical presentation of the patient.

Management

• For lesions that appear benign and asymptomatic, follow-up imaging at 3-6 months may be appropriate to ensure stability.
• If there are any concerning features such as rapid growth, pain, or pathologic fracture risk, biopsy should be considered after imaging characterization is complete.
• This comprehensive imaging approach allows for accurate diagnosis and appropriate management planning while avoiding unnecessary procedures for benign lesions.

From the Research

Recommended Imaging for Incidental Bone Cystic Lesion at the Proximal Humerus

The recommended imaging for an incidental bone cystic lesion at the proximal humerus includes:

• Radiographs to show an eccentric, lytic lesion with an expanded, remodeled "blown-out" or "ballooned" bony contour of the host bone, frequently with a delicate trabeculated appearance 2
• CT scanning to define the lesion, especially valuable for those lesions located in areas in which the bony anatomy is complex, and which are not adequately evaluated by plain films 2
• MRI to evaluate magnetic resonance imaging (MRI) characteristics of simple and aneurysmal bone cysts (SBC/ABC) of the proximal humerus, and to differentiate between the two in daily clinical routine 3
• MRI is also found to be an effective and reliable noninvasive technique for the diagnosis and follow-up controls of ABC, reducing the need for repeated radiographic examinations and exposure to ionizing radiation 4

Key Imaging Features

Key imaging features to look out for include:

• Fluid-fluid levels, which are common and may be seen on CT scans and MR images 2
• Circumferential and septal enhancement patterns on MRI, which correlate strongly with pathological fracture and histological diagnosis 3
• Unicameral morphology of lesions, which can be found in both SBC and ABC, making differentiation between the two entities challenging 3

Clinical Considerations

Clinical considerations include:

• Patient age, with younger patients (5 years or younger) being more likely to experience recurrence 5
• Cyst size, location, and activity level, which can affect the risk of recurrence 5
• Fracture pattern, with unimpacted fractures being more likely to result in recurrence 5